The objectives of this project are to find improved methods for the use of acrylic resin as a prosthetic material used in orthopedic surgery and dentistry, and to determine the toxic effects of the monomer, methyl methacrylate, which is released during curing in situ. As it is currently used, this resin has the disadvantages of a high curing temperature which can cause thermal necrosis of tissue around the implant, release of a toxic monomer into the general circulation during the polymerization reaction, and a less than satisfactory implant-to- bone bonding. The admixture of an additive to the cement can minimize or overcome these shortcomings without compromising the advantages of the resin itself, namely, its bioinertness, its strength, and, most important, its ability to be molded in situ. The improvement involves the admixture of an additive which lowers the curing temperature, reduces the release of monomer, and induces porosity. This latter allows the ingrowth of fibrous and bony tissue which stabilizes the implant. This project is aimed toward an evaluation of the composition of acrylic cement and additive which optimizes the efficacy of the acrylic cement within the confines of surgical requirements.